1. Field of the Invention
The present invention is directed to a method for controlling an X-ray device of the type having at least one X-ray tube and at least one X-ray detector, the X-ray tube and/or the X-ray detector being movably arranged. The invention also is directed to an X-ray device of this type.
2. Description of the Prior Art
Modern X-ray devices usually have not only a single X-ray tube/X-ray detector pair but generally contain a number of detectors that are permanently or movably installed or are mobile detectors. Either with or without a cable, such mobile detectors are freely movable at least within a range of action, for example within the X-ray room. A film foil cassette is an example of such a detector that is movable without a cable. The X-ray devices often additionally have a number of different fixed or movable X-ray tubes. An optimum system for implementing a specific examination is then constructed by selecting a detector and a matching X-ray tube. In the examination, it must then be assured that the desired X-ray tube and X-ray detector are suitably aligned relative to one another and relative to the examination subject, for example a body part of a patient, so that the X-rays passing through the examination subject strike the detector. It must also be assured that the corresponding detector is active and can pick up the X-rays. This is conventionally assured by an X-ray assistant, who aligns the X-ray tube and the X-ray detector relative to one another and relative to the examination subject and then determines that the corresponding detector is activated via a monitoring system attached to the X-ray detector, for example a flashing green light or a monitoring symbol displayed at an image station. The X-ray assistant then manually triggers the generation of the X-rays, and an image is acquired. When the X-rays are mistakenly triggered when the detector is not activated or when the X-ray tube and X-ray detector are not suitably positioned relative to one another, then the patient is exposed to the X-rays without the X-rays having an imaging effect. The exposure must then be repeated, which involves an additional radiation stress on the patient.
U.S. Pat. No. 6,200,024 discloses an X-ray diagnostic installation wherein the tube and the detector are respectively suspended independently of one another, compared to the known rigid connection of detector and tube via a C-arm, by means of which an active repositioning of the tube automatically effects an active repositioning of the detector or image intensifier. Mechanical sensors that know the respective location of the detector and the tube insure that a repositioning of the detector is automatically followed by a repositioning of the detector. The position of the detector and the tube thus can be acquired via the mechanical systems.